This invention relates generally to apparatus for filling a container with dry particulate material, and more particularly concerns a filling apparatus including an anti-dribbling filling nozzle having slanted air discharge ports for achieving dribble-free, clean-cutoff filling of a container with particulate materials such as toner.
Currently when filling particulate materials, for example toners into toner containers, toner is transported from the toner supply hopper into the container by a rotating auger. The auger is a spiral shaped mechanical part which pushes particles of toner inside a fill tube by direct mechanical contact. The nature of this mechanical contact process creates substantial limitations on accuracy and productivity of the toner filling operation. The speed of the toner movement in the fill tube is proportional to the speed of rotation of the auger and is limited by heat release due to auger/toner/funnel friction.
Toner containers for small low cost printers and copiers typically have a small opening into which the toner is to be added. Furthermore, the toner containers often have irregular shapes to conform to the allotted space within the copying machine. Therefore it becomes difficult to fill the toner container because of the small tube or nozzle required to fit into the small toner container opening and secondly for all the toner within the container to completely and cleanly fill the remote portions of the container before the container overflows.
In addition, during the filling operation there is some ordinarily undesirable continued discharge of toner (dribbling) from a conventional nozzle at cutoff or at the end of the filling cycle. In one embodiment, the end of a filling cycle occurs when the auger stops rotating and positive pressure normal to the axis of the auger is kept on for a fraction of a second longer in order to give some time for the toner or powder remaining in the nozzle to drop into the container. After that, the positive pressure is cut off and negative pressure in the form of a vacuum is turned on to xe2x80x9cfreezexe2x80x9d against the nozzle wall, any toner particles still remaining in the nozzle.
The main problem with this process is that when the positive pressure in the nozzle is switched to vacuum, this vacuum usually can firmly hold only a 3-5 mm thick layer of toner particles against the inner nozzle wall. Therefore in cases where the amount of toner remaining inside the nozzle is sufficient to create a layer thicker than 5 mm, the force of vacuum will be marginal (weak) for holding those toner particles on the top of the 5 mm layer surface. Thus, very often this force is not enough to hold them for more than 0.5-1 sec. Therefore, undesirable post-cutoff continued toner fallout or dribbling occurs when the filling apparatus indexes from one container to the next, thus resulting in dirty tops and/or sides of containers.
Conventional filling apparatus include conventional clean filling systems for use with such apparatus. Such a clean filling system is secured to filling line as well as to the toner conduit, and may be used to support a slide. The slide is connected to a tray or toner drip plate which slidably is fitted between the nozzle and the opening. A tray or drip plate in this position acts to prevent the spilling of powder during the indexing of containers. A housing which surrounds part of the nozzle, provides a cavity or chamber which is sealed when the tray or drip plate is in its closed position.
In accordance with the present invention, there is provided a method and apparatus for directing toner from a hopper containing a supply of toner to fill as well as cleanly cutoff filling of a container without post-cutoff dribbling. The apparatus includes (a) a conduit member connected to the hopper and having a discharging end for permitting a toner to be moved therethrough; (b) a conveyor device located at least partially within the conduit member for moving the toner from the hopper in a toner moving direction towards the container; and (c) an anti-dribbling nozzle device for directing the toner from the conveyor to cleanly fill the container. The anti-dribbling nozzle device includes a source of pressurized air, a controller, and a nozzle member that has a first end connected to the discharge end of the conduit member, a second and opposite end for dispensing moving toner into the container, and a nozzle wall connecting the first end to the second thereof. The nozzle wall includes slanted air discharging ports for discharging directed pulses of positive pressure air to forcibly remove powder from the nozzle wall, thereby enabling clean cutoff of powder flowing into the container without post-cutoff dribbling.